A liquid crystal panel included in a liquid crystal display device such as a liquid crystal television does not emit light, and thus a backlight device is required as a separate lighting device. The backlight device is arranged behind the liquid crystal panel (i.e., on a side opposite from a display surface side). The backlight device having a plurality of linear light sources and a diffuser sheet (optical member) that is provided on a light output side of the linear light sources has been known (see Patent Document 1).    [Patent Document] Japanese Unexamined Patent Publication No. 2007-279437